FileReader.readAsBinaryString()

O método readAsBinaryString é usado para iniciar a leitura dos conteudos de um especifico Blob ou File. Quando a operção da Leitura é terminada, o readyState retorna feito(DONE), e o loadend é acionada. Nesse tempo, o result atributo contem o binario bruto do ficheiro.

Note que este metódo não esta a ser usado conforme 12 Julho 2012 documentação da W3C.

Sintaxe

instanceOfFileReader.readAsBinaryString(blob);

Parametros

blob: O Blob ou File a ser Lido.

Exemplo

var canvas = document.createElement('canvas');
var height = 200;
var width  = 200;

canvas.width  = width;
canvas.height = height;

var ctx = canvas.getContext('2d');

ctx.strokeStyle = '#090';
ctx.beginPath();
ctx.arc(width/2, height/2, width/2 - width/10, 0, Math.PI*2);
ctx.stroke();

canvas.toBlob(function (blob) {
  var reader = new FileReader();

  reader.onloadend = function () {
    console.log(reader.result);
  }

  reader.readAsBinaryString(blob);
});

Specificações

Specification	Status	Comment
File API The definition of 'FileReader' in that specification.	Working Draft	Initial definition.

Feature	Firefox (Gecko)	Chrome	Internet Explorer*	Opera*	Safari
Basic support	3.6 (1.9.2)	7	10	12.02	6.0.2

Feature	Firefox Mobile (Gecko)	Android	IE Mobile	Opera Mobile	Safari Mobile
Basic support	32	3	10	11.5	6.1

Implementation notes

IE9 has a File API Lab.
Opera has partial support in 11.1.

Gecko-specific notes

Prior to Gecko 2.0 beta 7 (Firefox 4.0 beta 7), all Blob parameters below were File parameters; this has since been updated to match the specification correctly.
Prior to Gecko 13.0 (Firefox 13.0 / Thunderbird 13.0 / SeaMonkey 2.10) the FileReader.error property returned a FileError object. This interface has been removed and FileReader.error is now returning the DOMError object as defined in the latest FileAPI draft.

Veja Também

FileReader